This disclosure relates to a directional acoustic device and methods for manufacturing a directional acoustic device.
Acoustic devices include loudspeakers and microphones. Loudspeakers generally include a diaphragm and a linear motor. When driven by an electrical input signal, the linear motor moves the diaphragm to cause vibrations in air, thereby generating sound. Various techniques have been used to control the directivity and radiation pattern of a loudspeaker, including acoustic horns, pipes, slots, waveguides, and other structures that redirect or guide the generated sound waves. In some of these loudspeaker structures, an opening in the horn, pipe, slot or waveguide is covered with an acoustically resistive material to improve the performance of the loudspeaker over a wider range of frequencies, e.g., to increase the directionality of the loudspeaker. Microphones can have one or more microphone elements that receive sound instead of a diaphragm and linear motor that generate sound.